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author | chiba <chiba@30ef5769-5b8d-40dd-aea6-55b5d6557bb3> | 2003-05-18 15:34:30 +0000 |
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committer | chiba <chiba@30ef5769-5b8d-40dd-aea6-55b5d6557bb3> | 2003-05-18 15:34:30 +0000 |
commit | 0ed1ede707440a9a981c2e0cfd5421b0ba0e364d (patch) | |
tree | a4bc692f36e0ad999d9a92434311cff59e445caf /tutorial/tutorial2.html | |
parent | 088718bd207fd72ef411870a36ff0c09eaa153dc (diff) | |
download | javassist-0ed1ede707440a9a981c2e0cfd5421b0ba0e364d.tar.gz javassist-0ed1ede707440a9a981c2e0cfd5421b0ba0e364d.zip |
fixed a bug in CtBehavior#setBody().
git-svn-id: http://anonsvn.jboss.org/repos/javassist/trunk@19 30ef5769-5b8d-40dd-aea6-55b5d6557bb3
Diffstat (limited to 'tutorial/tutorial2.html')
-rw-r--r-- | tutorial/tutorial2.html | 91 |
1 files changed, 88 insertions, 3 deletions
diff --git a/tutorial/tutorial2.html b/tutorial/tutorial2.html index b9ca5bed..5016474a 100644 --- a/tutorial/tutorial2.html +++ b/tutorial/tutorial2.html @@ -363,11 +363,12 @@ For example, if the result type is <code>int</code>, then <code>($r)</code> does not convert a type; it does nothing. However, if the operand is a call to a <code>void</code> method, then <code>($r)</code> results in <code>null</code>. For example, +if the result type is <code>void</code> and +<code>foo()</code> is a <code>void</code> method, then <ul><pre>$_ = ($r)foo();</pre></ul> -<p>is a valid statement if the result type is <code>void</code>. -Here, <code>foo()</code> is a <code>void</code> method. +<p>is a valid statement. <p>The cast operator <code>($r)</code> is also useful in a <code>return</code> statement. Even if the result type is @@ -485,7 +486,74 @@ catch (java.io.IOException e) { <h3>5.2 Modifying a method body</h3> -<p><code>javassist.expr.ExprEditor</code> is a class +<p><code>CtMethod</code> and <code>CtConstructor</code> provide +<code>setBody()</code> for substituting a whole +method body. They compile the given source text into Java bytecode +and substitutes it for the original method body. + +<p>In the source text given to <code>setBody()</code>, the identifiers +starting with $ have special meaning + +<ul><table border=0> +<tr> +<td><code>$0</code>, <code>$1</code>, <code>$2</code>, ...    </td> +<td>Actual parameters</td> +</tr> + +<tr> +<td><code>$args</code></td> +<td>An array of parameters. +The type of <code>$args</code> is <code>Object[]</code>. +</td> +</tr> + +<tr> +<td><code>$$</code></td> +<td>All actual parameters.<br> +</tr> + +<tr> +<td><code>$cflow(</code>...<code>)</code></td> +<td><code>cflow</code> variable</td> +</tr> + +<tr> +<td><code>$r</code></td> +<td>The result type. It is used in a cast expression.</td> +</tr> + +<tr> +<td><code>$w</code></td> +<td>The wrapper type. It is used in a cast expression.</td> +</tr> + +<tr> +<td><code>$sig</code></td> +<td>An array of <code>java.lang.Class</code> objects representing +the formal parameter types. +</td> +</tr> + +<tr> +<td><code>$type</code></td> +<td>A <code>java.lang.Class</code> object representing +the formal result type.</td> +</tr> + +<tr> +<td><code>$class</code></td> +<td>A <code>java.lang.Class</code> object representing +the class currently edited.</td> +</tr> + +</table> +</ul> + +Note that <code>$_</code> is not available. + + +<p>Javassist allows modifying only an expression included in a method body. +<code>javassist.expr.ExprEditor</code> is a class for replacing an expression in a method body. The users can define a subclass of <code>ExprEditor</code> to specify how an expression is modified. @@ -1047,6 +1115,23 @@ public int ymove(int dy) { this.move(0, dy); } <p>Note that <code>$proceed</code> has been replaced with <code>this.move</code>. +<p>Javassist provides another way to add a new method. +You can first create an abstract method and later give it a method body: + +<ul><pre> +CtClass cc = ... ; +CtMethod m = new CtMethod(CtClass.intType, "move", + new CtClass[] { CtClass.intType }, cc); +cc.addMethod(m); +m.setBody("{ x += $1; }"); +cc.setModifiers(cc.getModifiers() & ~Modifier.ABSTRACT); +</pre></ul> + +<p>Since Javassist makes a class abstract if an abstract method is +added to the class, you have to explicitly change the class back to a +non-abstract one after calling <code>setBody()</code>. + + <h4>Mutual recursive methods</h4> <p>Javassist cannot compile a method if it calls another method that |